A variety of efficient operations can be performed with a machine tool having a multiple-axis control capability by using a numerical control unit (hereinafter referred to as an "NC unit") possessing a conversational-type automatic programming function. A conversational-type programming apparatus ordinarily has a parameter program function which enables the ready programming of similarly shaped workpieces, canned cycles, schedule operations and the like by inputting parameters. The apparatus allows one to input machining shapes merely by inputting the necessary data while observing a display screen. More specifically, conversational-type programming is characterized in that when various data are input, such as the amount of a tool correction and machining dimensions, as well as control parameters, such as machine tool backlash amount, feed rate and an acceleration/deceleration time constant, reference graphics relating to material shape, machining shape, tool shape and tool path and the like can be displayed on a display screen, thereby facilitating program creation and verification of the relevant conditions.
However, even though the graphics are displayed on a screen calling for the input of conversational data, the operator is required to have considerable skill when the machining operation is of a complicated nature. For example, after having selected a drilling menu display in a process selection step, the operator attempts to respond to prompts on the screen by inputting data corresponding to predetermined parameter items in the menu. At such time the parameters shown on a design drawing are input as data representing portions of the displayed graphic, but a beginner frequently has trouble in determining which parameters should be input as what data. This difficulty becomes even more pronounced with smaller referential graphics, more complicated graphics and when a large number of parameter items appear on the same page of the display.
As a consequence of the foregoing, a beginner is compelled to operate data setting keys such as input keys while referring not only to the display screen and design drawing but also to an operation manual. The problem is that this procedure requires a considerable amount of labor until skill is developed.
The present invention has been devised in view of the foregoing circumstances and its object is to provide a conversational programming apparatus capable of being operated in a simple manner even by an operator handling the machine for the first time.